Crystal structure and function of C-terminal Sau3AI domain.
Sau3AI is a type II restriction enzyme that recognizes the 5'-GATC-3' sequence in double-strand DNA and cleaves at 5' to the G residue. The C-terminal domain of Sau3AI (Sau3AI-C), which contains amino acids from 233 to 489, was crystallized and its structure was solved by using the Multi-wavelength Anomalous Diffraction method. The Sau3AI-C structure at 1.9 A resolution is similar to the structure of MutH, a DNA mismatch repair protein that shares high sequence similarity with the N-terminal Sau3AI domain. The functional analysis shows that Sau3AI-C can bind DNA with one recognition sequence but has no cleavage activity. These results indicate that Sau3AI is a pseudo-dimer belonging to the type IIe restriction enzymes and the Sau3AI-C is the allosteric effector domain that assists DNA binding and cleavage.
Xu
Chun-Yan
CY
Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China.
Yu
Feng
F
Xu
Si-Jie
SJ
Ding
Yu
Y
Sun
Li-Hua
LH
Tang
Lin
L
Hu
Xiao-Jian
XJ
Zhang
Zhi-Hong
ZH
He
Jian-Hua
JH
D000595:Amino Acid Sequence; D020137:Base Pair Mismatch; D001665:Binding Sites; D018360:Crystallography, X-Ray; D004260:DNA Repair; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism; D015252:Deoxyribonucleases, Type II Site-Specific / Q000737:chemistry* / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid
D004268:DNA-Binding Proteins; D010446:Peptide Fragments; D015252:Deoxyribonucleases, Type II Site-Specific; C024405:GATC-specific type II deoxyribonucleases